This booklet produced by the Science Enhancement Programme (SEP) is mainly aimed at Key Stage 4 but can be used as an introduction to Memory Shape Alloys. The following two activities can be used to model the way in which the latest ‘smart’ or ‘shape memory’ alloys work and introduces some of their applications.
Activity B1 page 36 shows a good way of introducing the principles of the shape memory effect using a model of a robotic arm. The model uses two pieces of thin smart wire connected to a lever on either side of a pivot. When a battery is connected to one of the smart wires, the wire contracts (by about 5%) and the lever moves. If the battery is disconnected, and current is now passed through the other wire, the lever moves back in the opposite direction. When a smart wire is used like this it is also called muscle wire.
Activity B5 page 41 demonstrates how the principles of training a smart alloy can be explored quite simply using a piece of memory wire. Training a sample of a smart alloy generally involves a complex process of treatment over a number of cycles in which it is deformed, heated and cooled.